A peculiarly shy plant sometimes seems to sprout from the seabed, appearing within seconds and disappearing just as quickly at the first sign of a predator. What looks like a blade of seagrass, moving oddly against the currents, is actually a fish—a garden eel. These alien creatures have developed an unusual feeding strategy. Unlike other organisms that feed on plankton, they do not swim freely, but instead anchor into burrows in the shape of sinusoidal waves, supported by mucus from their skin glands. Researchers from the Hebrew University of Jerusalem, Israel, studied their feeding behavior in the Red Sea. In gentle currents, the garden eels extended their bodies up to 60cm above the seabed. In more swiftly moving waters however, they curled into a question mark shape as low to the seabed as 20cm, their heads oriented against the current. This reduces the forces dragging on them significantly. While strong currents cause a decrease in feeding efficiency in other fish, by holding close in this way the garden eel is able to take full advantage of the increased influx of their prey. These findings show that being a shy stay-at-home can be a successful life strategy, too.
This colored ink drawing mixes with video footage of the characteristic garden eel head movement: ink and pixels flow together.
Sources: Khrizman, Alexandra et al., “Life in the flow: unique adaptations for feeding on drifting zooplankton in garden eels”, in Journal of Experimental Biology, vol. 221, issue 16, (2018).
Tyler, James C. and C. Lavett Smth, “Systematic Significance of the Burrow Form of Seven Species of Garden Eels (Congridae: Heterocongnnae)”, In American Museum Novitates, (1992).